Consider the following statements: DNA Barcoding can be a tool to: 1. assess the age of a plant or animal. 2. distinguish among species that look alike. 3. identify undesirable animal or plant materials in processed foods. Which of the statements given above is/are correct?

Answer: D. Statements 2 and 3 are correct; Statement 1 is wrong. DNA BARCODING is a taxonomic technique that uses a SHORT, STANDARDISED SECTION OF DNA from a specific gene to identify species. The gene typically used is mitochondrial COX1 (cytochrome c oxidase subunit I) for animals; rbcL and matK for plants; ITS for fungi. Statement 1 is WRONG. DNA barcoding CANNOT ASSESS THE AGE of a plant or animal. Age determination requires growth-ring analysis (dendrochronology in trees), radiocarbon dating in dead samples, otolith analysis in fish, telomere length analysis, or methylation 'clocks' — none of which is what barcoding does. Barcoding identifies species, not life-stage age of an individual. Statement 2 is CORRECT. The CORE PURPOSE of DNA barcoding is to DISTINGUISH AMONG SPECIES THAT LOOK ALIKE (morphologically cryptic species). Closely related species, juveniles vs adults, female vs male, or fragmentary specimens that defy visual identification can be reliably told apart by their DNA barcode sequences. This is particularly valuable for insects, microscopic organisms, and damaged specimens. Statement 3 is CORRECT. DNA barcoding is widely used to IDENTIFY UNDESIRABLE PLANT OR ANIMAL MATERIALS IN PROCESSED FOODS. Examples: detecting mislabelled fish (cheaper species sold as expensive ones), identifying meat species in adulterated products (the 2013 European horsemeat scandal used DNA testing), checking herbal supplements for substitution with fillers or contamination. FSSAI and global food safety agencies routinely use DNA-based species identification. Source: NCERT Class 12 Biology (Biotechnology and its Applications) / FSSAI food authentication guidelines.